<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CSS引入</title>
    <style>
        /*通过标签名选择器找到元素*/
        h2{color: #5900ff}
    </style>
    <!--引入外部css样式文件-->
    <link rel="stylesheet" href="my.css">
</head>
<body>
<h1 style="color: #ff0000">内联测试1</h1>
<h1 style="color: #00a1ff">内联测试2</h1>
<h2>内部测试1</h2>
<h2>内部测试2</h2>
<h3>外部样式1</h3>
<h3>外部样式2</h3>
</body>
</html>